\begin{tikzpicture}[>=Stealth, scale=0.8]
    \draw (0, 0) rectangle (6, 1);
    \draw (2, 0) -- (2, 1);
    \draw (4, 0) -- (4, 1);
    \node at (1, 1.3) {百位};
    \node at (3, 1.3) {十位};
    \node at (5, 1.3) {个位};
    \node at (1, -0.8) {$P_9^1$};
    \draw[decorate,decoration={brace,mirror,amplitude=0.2cm}] (2, -0.1) -- (6, -0.1);
    \node at (4, -0.8) {$P_9^2$};
\end{tikzpicture}
